الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 156 |  |  |
| | | from | 156 | | |
Abstract
Two field experiments were carried out at the farm of Agric. Res.
Center, Giza, Egypt, during 1993/1994and 1994/1995 seasons to manage
flax irrigation (scheduling irrigation according to the Class A pan
evaporation records) under three sowing dates. The effect of sowing dates
and irrigation regimes on flax yield and its components, oil content, some
technological character of fibers, and the crop water use were studied. Also,
the potential evapotranspiration and Class A pan relation to climate and
crop water use were estimated.
Flax cultivar, Giza 8 a double purpose variety was used in both
seasons. The experimental design was split-plot with four replications.
Sowing date treatment were arranged at random in the main plots and the
irrigation regunes (scheduling irrigation) treatments were assigned
randomly with the sub-plots. The sub-plot area was 10.5 m2 (3.0 x 3.5 m)
and each sub-plot was isolated by leaves 1.2 from other plots to avoid the
water lateral movements during irrigation. The experimental treatments
were as follows:
A. Sowing dates
1. Early sowing
2. Medium sowing
3. Late sowing
(October 2o&b)
(November 1dh)
(December Ill)
The period between intervals were 3-weeks.
B. Irrigation regimes
11: Irrigation at 0.8 accumulative pan evaporation (APE)
h: Irrigation at 1.0 accumulative pan evaporation
h: Irrigation at 1.2 accumulative pan evaporation
:4: Irrigation at 1.4 accumulative pan evaporation
The Class A pan used in the recommended type by the World Meteorological
Organization. It located very close to field and all factors affecting its records were
considered. The available soil moisture in the soil profile from soil surface til145.0
em depth has been converted to units of water depth in mm and was found to be
82.0 mm. The crop plants were irrigated when the water balance in the root zone
reached zero, i.e. irrigation when the accumulative pan evaporation records
multiplied by the rates 0.8, 1.0, 1.2 or 1.4 are equal to the available soil moisture
content or to 82.0 mm.
The soil was clay loamy with pH of 7.4 Flax seeds were broadcasted at the
rate of60.0 kg/fed. Calcium super phosphate (15.5 P20S) was applied at the rate of
100 kgslfed before planting. Nitrogen fertilizer was added in the form of urea
(46.0% N) at the rate of 70 kg N/fed. in two doses. The normal cultural practices
for growing flax were used during the two seasons. Irrigation regime treatments
were applied after the first irrigation till the end of the growing season.
Characters studied:
L Yield and yield components
1. Total plant height (em).
2. Technica1length (ern).
3. Number of fruiting branches/plant.
4. Stem diameter (mm).
5. Capsules number/plant.
6. Seeds number/plant.
7. Seed yield/plant (gm),
8. lOOO-seed weight (gm)
_ .._----
128
9. Straw yield/plant (gm).
10. Seed yield (Kg/fed).
11. Straw yield (Kg/fed).
12. Fiber yield (Kg/fed).
II. Oil content
1. Oil percentage in seeds (%)
2. Oil yield (kgslfed)
ID. Technological properties offiben
1. Fiber percentage, (%)
2. Fiber length (em),
3. Fiber strength (RKm.),
4. Fiber fineness (N. m.)
IV. Crop water use:
1. Actual evapotranspiration (ETc)
i. Seasonal ET (em}
ii. Daily ET rates (mm/day)
2. The Class A pan evaporation studies:
i. Pan evaporation and some climatic factors relations.
ii. Pan evaporation and actual daily Et rates relation
3. Potential evapotranspiration (ETp)
i. Monthly ETp
ii. Seasonal ETp
4. Crop coefficient (Kc)
5. Water use efficiency (WUE)
i. WUE in kg seeds/m” water
129
ii. WUE in kg fibers/m’ water.
The main results can be summarized as follows:
I. Yield and yield components:
A. Effect of sowing dates:
1. Sowing flax early on October 2<YUsignificantly increased total plant
height, technical length. number of fruiting branches/plant, stem
diameter, 1000-seed weight, straw yield/plant and per feddan in
both seasons.
2. Capsule number/plant, seed number/plant, seed yield/plant and per
feddan, as well as fiber yield/feddan were increased significantly
when flax plants were sown on November 10th in 1993/94 and
1994/95 seasons.
3. The late sowing of December 1g produced the lower means of yield
and yield components in the two seasons under study.
b. Effect of irrigation regimes:
1. Total plant height, technical length, stem diameter, straw yield/plant
and per feddan were significantly higher when irrigation was
practiced at 1.4 accumulative pan evaporation (short irrigation
intervals), in the two seasons.
2. Irrigating flax plants at 1.2 accumulative pan evaporation (APE)
significantly increased number of fruiting branches/plant, capsules
number/plant, seeds number/plant, seed yield/plant, 100o-seed
weight, seed and fiber yield/feddan than irrigation at 1.4, 1.0 or 0.8
APE in 1993/94 and 1994/95 seasons.
- -- --- --- - ---
130
3. Prolonged irrigation intervals (irrigation at 0.8 APE) produced
significant decreases in flax yield and its components in both
seasons.
C. Effect of the interaction:
1. Total plant height. technical length, stem diameter, straw yield per
plant and per feddan were significantly increased to higher values
when flax was sown on October 20th(early) and plants irrigated at
1.4APE (short intervals) in both seasons.
2. Sowing flax on October 20th and irrigation at 1.2 APE (moderate
intervals) produced the higher means of number of fruiting
branches/plant and 1000-seed weight in the two seasons under
study.
3. The second sowing date (November 1<Yh) and practicing irrigation
at 1.2APE (moderate intervals) significantly increased capsules and
seeds number/plant, seed yield/plant, seed yield/fed and fiber
yield/fed to their higher values in 1993/94 and 1994/95 seasons.
4. The lower means of yield and yield components were observed
from delaying sowing date of flax to the first of December and
subjecting plants to water stress or irrigation at 0.8 APE (prolonged
irrigation intervals) in both seasons.
n.Oil content
A. Effect of sowing dates:
1. The higher oil percentages in flax seeds were 42.04 and 41.590/0,
obtained from the second sowing date (Novemebr loth) in 1993/94
and 1994/95 seasons, respectively.
131
2. Sowing flax 3~week early or later than November lo!h significantly
decreased oil percentage in seeds.
3. The early and the late sowing of flax (October 2o!h or December
1M) reduced oil yield/fed significantly in both seasons.
4. Sowing flax on lo!h November produced the higher means of oil
yield i.e. 352.1 and 326.5 kgs/fed in 1993/94 and 1994/95 seasons,
respectively.
B. Effect of irrigation regimes:
1. Irrigating flax at short intervals (irrigation at 1.4 APE) gave the
higher means of oil percentage in seeds i.e. 40.14 and 39.67% in
the two successive seasons, respectively.
2. Oil percentage in seeds significantly decreased as soil moisture
decreased from irrigation at 1.4 APE to 1.2, 1.0 and 0.8 APE in
both seasons.
3. Oil yield/fed significantly increased when irrigation was applied at
1.2 APE in the two seasons under study.
C. Effect of the interaction:
1. The higher means of oil percentage in flax seed were 42.49 and
42.050/0, gained from sowing flax on November lo!!! and irrigation
at 1.4 APE.
2. Sowing flax on November lo!h and irrigation at 1.2 APE produced
the higher oil yield/feddan in the two seasons (386.3 and 359.5
kgs/fed).
132
ID. Technological properties of fibers:
A.Effect of sowing dates
1. Sowing flax on November 10th increased significantly fiber
percentage and fiber fmeness in 1993/1994 and 1994/1995 seasons.
2. The early sowing date (October 20th) produced the long fibers when
compared with the other two sowing dates in both seasons.
3. Delaying sowing date of flax from OCtober 2(jl1 to December 10!
significantly increased fiber strength to its higher values in the two
seasons under study.
B. Effect of irrigation regimes:
1. Irrigation flax at 1.2 APE gave the fiber percentage i.e. 14.34 and
13.460/0in 1993/1994 and 1994/1995, respectively.
2. Irrigation flax plants at short irrigation intervals i.e. irrigation at 1.4
APE significantly increased fiber length and fiber strength to its
higher values in both seasons.
3. The higher values of fiber fineness were obtained from irrigation at
long intervals (irrigation at 0.8 APE) in the two seasons under
study.
c. Effect of the interaction
1. Sowing flax on October 20th (early) and irrigation at 1.4 APE
increased fiber percentage significantly in both seasons.
2. The higher fiber length was obtained from sowing flax on
November lofu and irrigation at 1.2 APE in 1993/1994 and
1994/1995 seasons.
3. The later sowing of December 1~ and short irrigation inteIVals (1.
4
APE) produced the higher values of fiber strength.
4. Sowing flax on November lofu and irrigation at 0.8 APE
significantly increased fiber fineness to its maximum values in both
seasons.
IV. Crop water use
1. Actual evapotranspiration (ET)
A). Effect of sowing dates
i) Seasonal ET (em)
Seasonal £T values by flax irrespective to sowing dates and
irrigation regimes were 35.65 and 33.91 em in 1993/1994 and
1994/1995 seasons, respectively.
The early sowing of October 2(jb produced the highest ET values
i.e. 38.4 and 36.14 em in 1993/1994 and 1994/1995 seasons,
respectively.
Delaying sowing date than October 2# decreased seasonal ET by
flax to reach its lower values with December 1~ sowing (33.29 and
31.92 em) in both seasons, respectively.
ii) DaUy ET rates (mmlday)
The daily ET rates were low during two initial period (October and
November) and increased to reach its maximum. at mid-seasons
stage through February and March when plants aged 105 - 132, 84-
112 and 88 _ 119 day from sowing for the 1st, 2nd and 3rd sowing
dates, respectively, then redecreased again at late season stage
(maturity).
The maximum daily ET rates at the peak period of water
consumption were 3.05 mmJday, obtained from the early sowing
date in 1993/1994 seasons. whereas, in 1994/1995 seasons the later
sowing date gave the higher ET rate (3.00 mm/day) on March.
B) Effect of irrigation regimes
i) Seasonal ET (em)
Seasonal ET values were 30.55, 33.50, 37.26 and 41.28 em due to
irrigation flax at 0.8, 1.0, 1.2 and 1.4 APE in 1993/1994 season,
respectively. In 1994/1995 season the respective values ofET were
29.40,31.47, 35.43 and 39.33 em for the same irrigation treatments.
Seasonal ET values by flax plants increased when the available soil
moisture in the root zone increased (frequent irrigation intervals).
ii)Daily ETrates (mm/day)
Daily ET rates increased as the available soil moisture increased in
the root zone (increasing irrigation frequency) in both seasons.
The maximum values of daily ET rates in 1993/1994 season were
3.82, 3.74 and 3.83 mm/day, obtained from irrigating flax at 1.4
APE (short intervals) for the 1.@, 2J!Q and 3rd sowing dates,
respectively, which occurred on February and March (mid-season).
The same trend was found in 1994/1995 season and the values were
3.34,3.18 and 3.29 mm1day for the respective sowing dates.
2. The Class A pan evaporation studies
i) Pan evaporation and some climatic factors relation
The correlation between the daily Class A pan evaporation and
mean daily temperature, mean daily relative humidity and mean
daily vapour pressure deficit was highly significant in the two
seasons under study.
The correlation between daily evaporation records and mean daily
wind speed was not significant in the two seasons.
The correlation coefficient values between the Class A pan
evaporation and daily mean of air temperature, daily mean of
relative humidity and daily mean of vapour pressure deficit were
0.523,0.5426 and 0.4817, respectively.
The regression line of the relation between the Class A pan
evaporation rates (Y) and mean daily air temperature (X) can be
represented by the following formula;
y= 1.2721 + O.1399X
The linear regression for the relationship between the Class A pan
evaporation rate in mm/day (Y) and mean daily relative humidity
(X) is as follows:
y= 7.3719 + (-O.0569X)
The linear function of the Class A pan evaporation rate (Y) in
mm/day and mean daily vapour pressure deficit (X) in ml.bar
relationship can be estimated as follows:
y= 2.8148 + O.1051X
136
These results reveal that the Class A pan evaporation was closely
related to many climatic factor which affecting the evapotranspiration of
plants. Therefore, the Class A pan evaporation method is more accurate in
estimating short term fluctuations of the ETp and ET crop.
ii) Pan evaporation and actual ET relation
The relationship between the daily Class A pan records and daily
ETc of the early sowing date was not significant at any level of
irrigation in both seasons.
The Class A pan evaporation records were significantly correlated
with flax ET/day when plants were irrigated at 0.8 and 1.0 APE, for
the November lolli sowing in both seasons. However, pan daily
records were significant correlated with flax daily ET of the later
sowing at the levels of 0.8, 1.0, 1.2 and 1.4 APE in the two seasons.
It could be concluded that the Class A pan evaporation records can be
used a direct method for scheduling flax irrigation sown on November lo!U
and after that if it well located and all factors affecting evaporation were
considered.
3. Potential ET
i) Monthly ETp
, The monthly ETp values were somewhat high during the initial
period (October and November). Then monthly ETp values
decreased during December and increased again to reach its
maximum values during (grain filling) March, then redecreased at
late season stage.
Monthly values of ETp on March were 92.04 and 101.18 nun in
1993/1994 and 1994/1995 seasons, respectively.
ii) Seasonal ETp
Seasonal ETp values estimated by the Class A pan method in
1993/1994 season were 43.57, 40.97 and 40.25 em for the early,
moderate and late sowing dates, respectively. whereas, in
1994/1995 season, the ETp values were 41.81,39.16 and 38.06 cm
for October 2olli, November 10th and December Ig sowing dates,
respectively. These differences may be due to the differences in
growing season length of each sowing date.
4. Crop coefficient (Kc)
The crop coefficient values started with low rates during October
and November (initial period) and increased gradually after that to
reached its maximum value on February (mid-season), then
redecreased again till the end of season (April and May).
The Kc value ranged from (0.5-0.722) on October and November,
whereas its value at mid-season was 1.11. At late-season, it ranged
from 0.541 -0.557.
The higher Kc values at any growth stage (any month) of the
growing season were obtained from the early sowing date.
However, the lower monthly Kc values were resulted from the late
sowing date in both seasons.
Seasonal Kc were 0.856 and 0.854 in 1993/1994 and 199411995,
respectively.
Irrigation flax at 1.4 APE produced the higher monthly Kc values at
any growth stage in both seasons, as well as the seasonal Kc. The
lower ones were obtained from irrigation at 0.8 APE.
5. Water use efficiency (WUE)
i) WUE for seeds (kgs seeds/m” water)
Sowing flax on November tofu is more efficient in water utilization
than the early or the late sowing dates.
Each cubic meter of water applied to the medium sowing date
plants produced 0.575 and 0.558 kgs seeds in 1993/1994 and
1994/1995, respectively.
Irrigation flax plants at 1.2APE gave the higher values ofWUE i.e.
0.503 and 0.494 kgs seeds/m” water consumed in the two
successive seasons, respectively.
Sowing flax on November lofu and practiced irrigation at 1.2 APE
can be recommended for the better utilization of water by flax
plants.
ii) WUE for fibers (kgs flbers/m” water)
The higher values of WUE were 0.255 and 0.239 kgs fibers/m’
water consumed were resulted from sowing flax on November lo!l!
in both seasons.
Irrigation flax at 1.2 APE increased WUE to its higher values i.e.
0.228 and 0.217 kgs fibers/m”water in the two successive seasons,
respectively.
The medium sowing date (November loth) and irrigation at
moderate intervals (1.2 APE) gave the higher values ofWUE of
fibers/m’ water (0.266 and 0.256) in 1993/1994 and 1994/1995
seasons. respectively.
It could be concluded that the second sowing date (November loth)
and irrigating flax plants at 1.2 APE is more efficient practice in
utilizing water for seeds and fiber production.